I have just been trying the datapump facility for the first time and
have had mixed success.
With very simple src SQL like 'select * from table where field=value'
and dst SQL 'select * from table' it seems to be missing out some
columns.

If I look at ItemActions and click prepare then all the included
columns have ColumnName=DIRECT and the excluded have ColumnName=BASE:

What does BASE: mean? Why is it there? Is it what causes the column
to be excluded? Is the SQL is the right form?

Regards
Paul